Depending on the way you've set up your system, it might be as easy as copying the monitors.xml file from the correctly set-up user to all users:
To test this for one user:
cp --preserve=timestamps /home/CorrectUser/.config/monitors.xml /home/TestUser/.config/
then log off TestUser if already logged in, log back on and see whether everything is correct.
The command for all users:
cp /home/CorrectUser/.config/monitors.xml /tmp/
for szUser in /home/* ; do sudo cp --preserve=timestamps /tmp/monitors.xml $szUser/.config/ ; done
The command for the login screen:
sudo cp --preserve=timestamps /home/CorrectUser/.config/monitors.xml /var/lib/lightdm/.config/
The command for all future users¹:
sudo mkdir -p /etc/skel/.config
sudo cp --preserve=timestamps /home/CorrectUser/.config/monitors.xml /etc/skel/.config/
Note¹: All users you'll be creating in the future
To set your screen configuration for every user on log in (this will not change the configuration on the log in screen), you can create a .desktop file in /etc/xdg/autostart
find out the name of the screen you'd like to be rotated by running xrandr. It will output a number of lines, among thos a few lines looking like:
VGA-0 connected
This gives you information on the names of the connected screens.
VGA-0Create a launcher with (e.g.) gedit:
sudo -i gedit /etc/xdg/autostart/set_screens.desktop
Paste the text below into the file:
[Desktop Entry]
Name=set_screens
Exec=/bin/bash -c "sleep 10&&xrandr --output VGA-0 --rotate left"
Type=Application
replace in the line:
Exec=/bin/bash -c "sleep 10&&xrandr --output VGA-0 --rotate left"
The string: VGA-0 by your (rotated) screen's name.
In the line
Exec=/bin/bash -c "sleep 10&&xrandr --output VGA-0 --rotate left"
I included a sleep 10. That is because sometimes, xrandr commands break if they run too early, before the desktop is "finished" loading. Possibly you need to increase the break, or you could try leaving it out. In the command, as it is, the screen rotates after 10 seconds after log in of any user.
The command:
xrandr --output VGA-0 --rotate left
rotates the screen left, no need to say that if you'd like another type of rotation, you can choose either left, right, normal, inverted (see also here).
You can run commands on startup (actually log in) by placing a .desktop file (launcher) in ~/.config/autostart. This will only run the launcher for a single user. If you do the same, but place the launcher in /etc/xdg/autostart, the command runs whenever any user logs in, unless a specific user disables the launcher for him or her in Dash > Startup Applications
Additionally, you can simply copy your local ~/.config/monitors.xml file to /var/lib/lightdm/monitors.xml to also make the settings work on log in screen.
Imo the combination of this, and the solution above (a launcher in /etc/xdg) is the easiest solution to achieve exactly what you want for both the login screen and (any) user. Also, the solution of a launcher in /etc/xdg is (very) easily reversed or changed in case you'd need to make another setup, without editing many files on (each) user's level, since both the user's settings and the login screen are managed for all users at once in two simple files.
for Ubuntu 21.10 the display manager is gdm3 and the command to change the login screen resolution is
sudo cp -v ~/.config/monitors.xml /var/lib/gdm3/.config/
the other existing user can be set with
for u in /home/*
do
if [ "$u" != "$HOME" ]
then
sudo cp -v ~/.config/monitors.xml "$u/.config"
fi
done
and future users
sudo mkdir -v /etc/skel/.config/
sudo cp -v ~/.config/monitors.xml /etc/skel/.config/
Note: the -v is optional
NB: don't bother with /root the root user as you should NEVER login as root in the GUI it is very dangerous
Just wanted to add a comment for anyone finding this struggling with a similar issue. I was stuck with resolution of my old monitor (1280x1024) every time I log in, but the login screen and guest user login use the correct default 1680x1050.
I've read a lot of posts over the last four months looking for an answer, reading up on xorg.conf, monitors.xml, lightdm and xrandr and other suggestions - but some config changes are complicated and carry the risk of breaking the display entirely, so I ended up using the gui to change the monitor setting manually every login.
Today I did a grep for the old resolution in my .config folder.
grep -HrnIF '1280' .config | less
First result was ~/.config/autostart/xrandr.desktop file containing this,
Exec=xrandr -s 1280x1024 -r 75
so I just moved the file out of there. And bingo, I log in and get the default 1680x1050 resolution.
It took me a few hours of searching and I couldn't find a close enough answer, so posting here in case it's useful to someone.
You may wish to append something to /etc/lightdm/lightdm.conf. Here we create a script that uses an xrandr command to setup your display(s). You can use some graphical RandR tool to create a command for you, such as arandr. In my case, the script would look like:
#!/bin/sh
xrandr --output DVI-I-1 --mode 1600x1200 --pos 0x0 --rotate left --output DVI-I-0 --off --output DP-3 --off --output DP-2 --off --output DP-1 --mode 1600x900 --pos 1200x700 --rotate normal --output DP-0 --off
You can put this script in /usr/share or wherever you want. Your script may look far less complex, as this is for a complex dual-monitor setup. Then append something like:
session-setup-script=/usr/share/mycustomxrandr.sh
and:
display-setup-script=/usr/share/mycustomxrandr.sh
Make sure the file is executable, so:
chmod a+x mycustomxrandr.sh
The session-setup-script will set the display for after you login through LightDM, and display-setup-script will change the display for the login screen.
